Display system, electronic mirror system, and moving body

ABSTRACT

A display system includes a display surface and a display mirror. The display surface is configured to display image P1 based on a captured image. The display mirror is configured to reflect, as reflection image P2, only a partial area in the image displayed on the display surface. The display system is configured so that a position of reflection image P2 changes as a point of view of a subject viewing the display mirror moves.

TECHNICAL FIELD

The present disclosure generally relates to display systems, electronicmirror systems, and moving bodies, and, in particular, relates to adisplay system, an electronic mirror system, and a moving body, eachconfigured to display an image based on a captured image.

BACKGROUND ART

Such a conventional electronic mirror system is known that includes animaging device configured to capture a rear or side view image of avehicle, and a display device configured to display, as an image, animage signal output from the imaging device (PTL 1). Here, the displaydevice is disposed, inside the vehicle, at a position allowing a driverto easily view an image on the display device. A liquid crystal display,for example, constitutes the display device.

CITATION LIST Patent Literature

PTL 1: Unexamined Japanese Patent Publication No. 2009-83618

SUMMARY OF THE INVENTION

In the electronic mirror system described in PTL 1, a person viewing animage displayed on the liquid crystal display is less likely to acquirea sense of solidity.

The present disclosure has an object to provide a display system, anelectronic mirror system, and a moving body, each capable of providing asense of solidity to a person viewing a displayed image.

A display system according to one aspect of the present disclosureincludes a display surface and a display mirror. The display surface isconfigured to display an image based on a captured image. The displaymirror is configured to reflect, as a reflection image, only a partialarea in the image displayed on the display surface. The display systemis configured so that a position of the reflection image changes as apoint of view of a subject viewing the display mirror moves.

An electronic mirror system according to one aspect of the presentdisclosure includes the above described display system, and a cameraconfigured to output the captured image to the display system.

A moving body according to one aspect of the present disclosure includesthe above described electronic mirror system, and a moving body mainbody mounted with the electronic mirror system.

The present disclosure is capable of advantageously providing a sense ofsolidity to a person viewing a displayed image.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram of a vehicle equipped with a displaysystem according to a first exemplary embodiment and a third exemplaryembodiment.

FIG. 2 is a conceptual diagram illustrating a focal point of an eye of auser when the display system according to the first exemplary embodimentis used.

FIG. 3 is a conceptual diagram illustrating a position of a displaymirror in the vehicle applied with the display system according to thefirst exemplary embodiment.

FIG. 4 is a conceptual diagram illustrating a relationship between avisual field of the user of the display system according to the firstexemplary embodiment and a virtual image of an image displayed on adisplay surface.

FIG. 5A is a conceptual diagram illustrating a relationship between avisual field of the user of the display system according to the firstexemplary embodiment and a virtual image of an image displayed on thedisplay surface.

FIG. 5B is a conceptual diagram of a relative positional relationshipbetween an image in the above described display system and an imagereflected by the display mirror.

FIG. 6A is a conceptual diagram illustrating a relationship between avisual field of the user of the display system according to the firstexemplary embodiment and a virtual image of an image displayed on thedisplay surface.

FIG. 6B is a conceptual diagram of a relative positional relationshipbetween an image in the display system according to the first exemplaryembodiment and an image reflected by the display mirror.

FIG. 7 is a conceptual diagram illustrating a relationship between avisual field of a user of a display system according to a comparativeexample and a virtual image of an image displayed on a display surface.

FIG. 8 is a conceptual diagram illustrating a relationship between avisual field of the user of the display system according to the firstexemplary embodiment and a virtual image of an image displayed on thedisplay surface.

FIG. 9 is a conceptual diagram illustrating a position of a displaymirror in a vehicle applied with a display system according to a firstmodification to the first exemplary embodiment.

FIG. 10 is a conceptual diagram illustrating a relationship between avisual field of a user of the display system according to the firstmodification to the first exemplary embodiment and a virtual image of animage displayed on a display surface.

FIG. 11 is a conceptual diagram illustrating a relationship between avisual field of the user of the display system according to the firstmodification to the first exemplary embodiment and a virtual image of animage displayed on the display surface.

FIG. 12A is a conceptual diagram illustrating a relationship between aguide pattern image displayed on the display surface of the displaysystem according to the first modification to the first exemplaryembodiment and a reflection image.

FIG. 12B is a conceptual diagram illustrating a relationship between aguide pattern image displayed on the display surface of the displaysystem according to the first modification to the first exemplaryembodiment and a reflection image.

FIG. 12C is a conceptual diagram illustrating a relationship between aguide pattern image displayed on the display surface of the displaysystem according to the first modification to the first exemplaryembodiment and a reflection image.

FIG. 12D is a conceptual diagram illustrating a relationship between aguide pattern image displayed on the display surface of the displaysystem according to the first modification to the first exemplaryembodiment and a reflection image.

FIG. 13 is a conceptual diagram illustrating a configuration of adisplay system according to a second exemplary embodiment.

FIG. 14 is a conceptual diagram illustrating a configuration of thedisplay system according to the third exemplary embodiment.

FIG. 15A is a front view of a display element of the display systemaccording to the third exemplary embodiment.

FIG. 15B is a side view of the display element of the display systemaccording to the third exemplary embodiment.

FIG. 16A is a front view of a display element of a display systemaccording to a first modification to the third exemplary embodiment.

FIG. 16B is a side view of the display element of the display systemaccording to the first modification to the third exemplary embodiment.

FIG. 16C is a rear view of the display element of the display systemaccording to the first modification to the third exemplary embodiment.

FIG. 17 is a conceptual diagram illustrating a display element of adisplay system according to a second modification to the third exemplaryembodiment.

FIG. 18A is a conceptual diagram illustrating, with a pattern imagedisplayed, a display element of a display system according to a thirdmodification to the third exemplary embodiment.

FIG. 18B is a conceptual diagram illustrating the display systemaccording to the third modification to the third exemplary embodimentwith no pattern image displayed.

FIG. 19 is a conceptual diagram illustrating a display element of adisplay system according to a fourth modification to the third exemplaryembodiment.

FIG. 20 is a conceptual diagram illustrating a configuration of adisplay system according to a fifth modification to the third exemplaryembodiment.

FIG. 21 is a conceptual diagram illustrating an image reflected by adisplay mirror in a display system according to a sixth modification tothe third exemplary embodiment.

FIG. 22 is a conceptual diagram illustrating a configuration of adisplay system according to a fourth exemplary embodiment.

DESCRIPTION OF EMBODIMENTS

FIGS. 1 to 22 described in below exemplary embodiments, modifications,and comparative example, are merely conceptual diagrams. Ratios in sizeand thickness of components in the drawings do not always reflect actualdimensional ratios.

First Exemplary Embodiment

(1) Outline

Display system 10 according to the present exemplary embodiment is, asillustrated in FIG. 1, a system used in vehicle 100 representing amoving body, for example.

Display system 10 is mounted on main body (moving body main body) 110 ofvehicle 100. In display system 10, when image P1 (see FIG. 5B) based ona captured image is displayed on display surface 21, image (hereinafteralso referred to as reflection image) P2 (see FIG. 5B) reflected bydisplay mirror 3 is viewed by user 200 (driver of vehicle 100) who is asubject viewing display mirror 3. Display mirror 3 is disposed, proximalto windshield 102 , on a front side portion of ceiling portion 101 ofmain body 110, at a position in a viewing field of user 200, when user200 seated on front seat 103 faces forward (see FIG. 1). A capturedimage is output from camera (imaging device) 90 configured to capture arear view image of vehicle 100. Camera 90 is mounted on main body 110 ofvehicle 100. User 200 views reflection image P2 with display mirror 3.Therefore, user 200 views as if a part of image P1 on display surface 21is displayed in a space that is distal from display mirror 3, based ontheir eyes (eye balls) 201 (see FIG. 2). In other words, user 200 viewsas if, in a direction in which user 200 can view display mirror 3,virtual image 301 (see FIGS. 2 and 5A) of a part of image P1 on displaysurface 21 is displayed at a position in front of vehicle 100.

With the electronic mirror system described in PTL 1, however, a driverof a vehicle views an actual image displayed on a display deviceincluding a liquid crystal display. Therefore, for the driver, forexample, a distance difference between a distance to a position at whicheyes focus on when viewing a road situation in front of the vehicle anda distance to a position at which the eyes focus on when viewing animage on the display device becomes greater, thus increasing an amountof focus adjustment and extending a time for focusing (focal pointadjustment).

On the other hand, with display system 10, as illustrated in FIG. 2,distance difference ΔL between distance L1 to a position at which eyes201 focus on when viewing a road situation in front of vehicle 100 anddistance L2 to a position at which eyes 201 focus on when viewingvirtual image 301 becomes smaller. Therefore, with display system 10,user 200 can reduce an amount of focus adjustment, as well as user 200can shorten a time for focusing. With display system 10, even when user200 is aged or far sighted, for example, and accordingly facesdifficulty in focusing on a position at a relatively shorter distance,an easy focus adjustment can be achieved.

Display system 10 is configured so that a position of reflection imageP2 showed as virtual image 301 at a distal position changes as a pointof view of user 200 viewing display mirror 3 (eyes 201 of user 200)moves. Therefore, display system 10 is capable of advantageouslyproviding a sense of solidity on another vehicle, for example, runningbehind user 200 viewing virtual image 301, compared with a case when adriver directly views a display device displaying, as an image, an imagesignal output from an imaging device.

(2) Configuration

(2.1) Whole Configuration of Display System

Display system 10 according to the present exemplary embodimentincludes, as illustrated in FIGS. 1 to 6B and FIG. 14, display unit(image forming unit) 2 and display mirror 3. Display unit 2 has displaysurface 21. Display system 10 further includes a controller (notillustrated) configured to control display unit 2.

Display surface 21 is configured to display image P1 based on a capturedimage output from camera 90. Camera 90 is not a component of displaysystem 10. An image element in camera 90 is a Complementary MOS (CMOS)image sensor. The image element is not limited to the CMOS image sensor,but may be a Charge Coupled Device (CCD) image sensor, for example.

Display unit 2 outputs light to form an image. Display unit 2 includes,as illustrated in FIG. 14, liquid crystal panel 22 (Liquid CrystalDisplay or LCD) and light source device 23. Liquid crystal panel 22 isdisposed in front of light source device 23. Light source device 23 isused as a backlight for liquid crystal panel 22. Light source device 23is a surface light source. Light source device 23 is a side light typelight source device using a solid light-emitting element, such as alight emitting diode or a laser diode. Light from light source device 23passes through liquid crystal panel 22, and is output from displaysurface 21 of display unit 2. Light output from display surface 21 islight reflecting an image displayed on liquid crystal panel 22. FIG. 14schematically illustrates an advancing path (optical path OP) of light(output light) output from a point (pixel point) on image P1 displayedon display surface 21 of display unit 2.

In display system 10, a lengthwise of liquid crystal panel 22 representsa lengthwise of reflection image P2, while a widthwise of liquid crystalpanel 22 represents a widthwise of reflection image P2. The lengthwiseof reflection image P2 represents a lengthwise of virtual image 300 (seeFIGS. 5A and 6A), in other words, a direction along a vertical directionin a visual field of user 200. The widthwise of reflection image P2represents a widthwise of virtual image 300 of image P1, in other words,a direction along a horizontal direction in the visual field of user200.

The controller controls display unit 2 (liquid crystal panel 22 andlight source device 23). Here, the controller acquires a captured imageoutput from camera 90, and causes display unit 2 to display image P1based on the captured image. The captured image is a rear view image ofvehicle 100 captured and generated by camera 90 mounted on a rearportion of vehicle 100. As an example, the controller causes displayunit 2 to display, as image P1, an acquired captured image as is. Here,camera 90 is disposed on the rear portion of vehicle 100 at a center ina left-right direction. Therefore, camera 90 can capture an area behindcamera 90 (within visual field FV9 of camera 90 in FIG. 1). Displaysystem 10 can be applied to electronic mirror system 80. Electronicmirror system 80 includes display system 10, and camera 90 configured tooutput a captured image to display system 10. Electronic mirror system80 can be used as an inside mirror of vehicle 100.

The controller includes, for example, a microcomputer mainly including aCentral Processing Unit (CPU) and a memory. In other words, thecontroller is achieved by using a computer including a CPU and a memory.The CPU executes a program stored in the memory, allowing the computerto function as the controller. Herein, the program is recorded inadvance in the memory of the controller. However, the program may beprovided via a telecommunication line such as the Internet or by beingrecorded in a recording medium such as a memory card.

Display mirror 3 is a concave mirror. Display mirror 3 includes, as anexample, a glass base material, and a reflection film formed on aconcave surface of the base material. The reflection film is a metalfilm, for example.

Display mirror 3 is configured to reflect image P1 displayed on displaysurface 21. Display mirror 3 in display system 10 reflects, asreflection image P2, only a partial area in image P1 displayed ondisplay surface 21.

In display system 10, as illustrated in FIG. 4, a size of display mirror3 is determined so that a size of virtual image 300, with respect towhole image P1, on a virtual plane in a space away from user 200 isgreater than a size of visual field VF2 of eyes 201 of user 200, whichis determined by display mirror 3. Here, in display system 10, the sizeof display mirror 3 is determined so that an outer peripheral line ofvisual field VF2 on the above described virtual plane lies inside anouter peripheral line of virtual image 300. Therefore, display system 10is configured so that a position of reflection image P2 changes as eyes201 of user 200 (subject) viewing display mirror 3 move (see FIGS. 5A,5B, 6A, and 6B). Here, reflection image P2 has a less number of pixelsthan a number of pixels in image P1 in both the lengthwise and thewidthwise of image P1.

For description purposes, two eyes 201 of user 200 hereinafter may bereferred to as right eye 201R and left eye 201L to distinguish from eachother. In below descriptions with reference to FIGS. 5A and 6A, the term“right side” refers to a right side when viewed by user 200, while theterm “left side” refers to a left side when viewed by user 200.

FIG. 5A is a conceptual diagram when a center point of a straight lineconnecting right eye 201R and left eye 201L of user 200 and a center ofdisplay surface 21 both lie within vertical surface VP. FIG. 6A is aconceptual diagram when the center point of the straight line connectingright eye 201R and left eye 201L of user 200 moves rightward from theposition in FIG. 5A, and right eye 201R moves to a right end of eye-box203. The term “eye-box 203” used herein denotes an area within whichuser 200 can view an image without any omissions. More specifically, theterm “eye-box 203” used herein denotes an area of view in a whole visualfield of eyes 201, in which a part of virtual image 300 is reflected. Indisplay system 10, when eyes 201 of user 200 are within an area ofeye-box 203, reflection image P2 is within image P1, as illustrated inFIGS. 5B and 6B.

As illustrated in FIGS. 5A and 6A, virtual image 301 formed when displaymirror 3 reflects a part of image P1 represents a part of virtual image300 formed when image P1 displayed on display surface 21 is fullyreflected by a concave mirror 30 according to a comparative example (seeFIGS. 7 and 8 described below). In FIG. 5A, a central portion of wholevirtual image 300 in both an up-down direction and a left-rightdirection represents virtual image 301 that is viewable by user 200.

FIG. 5A illustrates an area of virtual image 301 in virtual image 300,which is viewable by right eye 201R of user 200. An area of virtualimage 301, which is viewable by left eye 201L of user 200, is planesymmetry to the area of virtual image 301, which is viewable by righteye 201R, with respect to vertical surface VP.

As illustrated in FIG. 6A, as the center point on the straight lineconnecting right eye 201R and left eye 201L of user 200 moves rightwardrelative to the position illustrated in FIG. 5A, the area of virtualimage 301, which is viewable by right eye 201R of user 200 movesleftward. In FIG. 6A, right eye 201R of user 200 lies at right end 203Rof eye-box 203, and left end 301L of virtual image 301, which isviewable by right eye 201R of user 200, is in alignment with left end300L of virtual image 300.

In contrast to FIG. 6A, as the center point on the straight lineconnecting right eye 201R and left eye 201L of user 200 moves leftwardrelative to the position illustrated in FIG. 5A, the area of virtualimage 301, which is viewable by left eye 201L of user 200, movesrightward. When left eye 201L of user 200 moves to left end 203L ofeye-box 203, right end 301R of virtual image 301, which is viewable byleft eye 201L of user 200, is in alignment with right end 300R ofvirtual image 300.

Therefore, in display system 10, when user 200 moves their face in theleft-right direction, similar to a case when user 200 views the insidemirror, the areas of virtual image 301, which are respectively viewableby right eye 201R and left eye 201L, change as user 200 moves theirface. Here, as long as right eye 201R and left eye 201L of user 200 arewithin eye-box 203, an image can be viewed without any omissions.

In display system 10, even when user 200 moves their face in the up-downdirection, similar to a case when user 200 views the inside mirror, theareas of virtual image 301, which are respectively viewable by right eye201R and left eye 201L, change as user 200 moves their face. In otherwords, when user 200 moves their face upward, the areas of virtual image301, which are respectively viewable by right eye 201R and left eye201L, move downward, while, when user 200 moves their face downward, theareas of virtual image 301, which are respectively viewable by right eye201R and left eye 201L, move upward. Here, as long as right eye 201R andleft eye 201L of user 200 are within eye-box 203, an image can be viewedwithout any omissions.

Display system 11 according to the comparative example will now bedescribed with reference to FIGS. 7 and 8.

Display system 11 according to the comparative example is a Head-UpDisplay (HUD). Display system 11 includes display unit 20 and concavemirror 30, instead of display unit 2 and concave mirror 3 in the firstexemplary embodiment. In display system 11, as illustrated in FIGS. 7and 8, as long as a point of view of user 200 is within eye-box 203,even when eyes 201 of user 200 move, virtual image 300 of a whole imagedisplayed on display surface 211 of display unit 20 is identical tovirtual image 311 formed when concave mirror 30 reflects the image.

On the other hand, in display system 10 according to the presentexemplary embodiment, display mirror 3 reflects, as reflection image P2,only a partial area in image P1 displayed on display surface 21. Displaysystem 10 is configured so that a position of reflection image P2changes as the point of view of user 200 viewing display mirror 3 moves.Therefore, display system 10 is capable of advantageously providing asense of solidity to user 200, compared with a case when a driverdirectly views a display device displaying, as an image, an image signaloutput from an imaging device.

In display system 10, it is advantageous that a resolution of image P1displayed on display surface 21 be higher than a limit resolution ofvirtual image 300 at a position of virtual image 300 being located. Theterm “limit resolution of virtual image 300 at a position of virtualimage 300 being located” (hereinafter simply referred to as limitresolution) used herein denotes a value determined by a visual distancefrom eyes 201 of user 200 to virtual image 300 and visual acuity of user200. A limit resolution refers to a limit value of a resolutionidentifiable by human's eyes, and can be acquired based on a gap of aLandolt ring used in a visual acuity test, for example. A value of alimit resolution lowers as a visual distance extends longer, and a valueof a limit resolution becomes greater as user 200 has higher visualacuity. A limit resolution can be acquired from a predeterminedcalculating formula with a value of a visual distance from eyes 201 ofuser 200 to virtual image 300 and a value of visual acuity of user 200.In display system 10 according to the present exemplary embodiment,display mirror 3 expands and displays a part of an image on displaysurface 21, thus determining, when a limit resolution is determined, aresolution of image P1 on display surface 21 in accordance with thelimit resolution, and setting a resolution of image P1 to a value thatis higher than a value of the limit resolution. As described above, oncea resolution of image P1 on display surface 21 is determined, virtualimage 300 is displayed at a resolution that is higher than a limitresolution at a position of virtual image 300 being displayed, thusproviding, to user 200 viewing virtual image 300, a sense of depth and asense of solidity in virtual image 300, as if user 200 is viewing amirror. In particular, while vehicle 100 is traveling, a high-definitionimage moves as vehicle 100 moves, and user 200 can further acquire asense of solidity.

Display system 10 is not limited to a case in which display mirror 3 isdisposed in front of user 200, as illustrated in FIGS. 3, 5A, 5B, 6A,and 6B, for example, but may be applied to a case in which displaymirror 3 is disposed on a left side in front of user 200, as illustratedin FIGS. 9 to 11, for example. In FIGS. 10 and 11, both left eye 201Land right eye 201R of user 200 face diagonally left forward.

FIG. 10 illustrates an area of virtual image 301 in virtual image 300,which is viewable by right eye 201R of user 200. FIG. 11 illustrates anarea of virtual image 301 in virtual image 300, which is viewable byleft eye 201L of user 200. In both cases, virtual image 301 is smallerthan virtual image 300.

In display system 10, housing 28 accommodating display unit 2 and thecontroller, and housing 38 accommodating display mirror 3 are separatefrom each other (see FIG. 3, for example). However, this is merely anexample. Display unit 2, the controller, and display mirror 3 may beaccommodated in a single housing, for example.

In display system 10, a reflection rate and a penetration rate ofdisplay mirror 3 may be respectively specified to 80% and 20%, forexample, and, on a back surface of display mirror 3, a display deviceconfigured to display a warning icon may be disposed. Therefore, evenwhen the point of view of user 200 moves, the warning icon can be alwaysviewed.

(2.2) Operation of Electronic Mirror System

Operation of electronic mirror system 80 will now be described. Forexample, when a battery of vehicle 100 supplies power to electronicmirror system 80, and an Electronic Control Unit (ECU) enters a controlsignal causing electronic mirror system 80 to start operating,electronic mirror system 80 starts operating.

For example, when the ECU of vehicle 100 enters a control signal to thecontroller, the controller causes camera 90 to capture a rear view imageof vehicle 100 at a predetermined frame rate, and acquires image data onthe captured image from camera 90.

When the image data on the captured image is entered from camera 90, thecontroller causes display unit 2 to display, on display surface 21,image P1 based on the captured image.

(3) Mirror Position Adjustment Guide Pattern

FIG. 12A illustrates how display mirror 3 shows, in display system 10,image P1 based on a captured image and an image reflected by displaymirror 3 (hereinafter also referred to as reflection image) P2. Asdescribed above, it is advantageous that reflection image P2 be at anapproximately center of image P1. However, when a mirror position isadjusted, reflection image P2 might be located at a position inclinedwith respect to image P1, as illustrated in FIG. 12B. In this case,mirror position adjustment guide pattern P3 is displayed on image P1, asillustrated in FIG. 12C. Mirror position adjustment guide pattern P3 isa triple frame pattern, for example, where inside of the frame istransparent so that reflection image P2 is reflected inside. It isadvantageous that a size of the frame be a size fully accommodatingreflection image P2. Mirror position adjustment guide pattern P3 may bea single frame or a double frame, as long as an image can bedistinguished, or may be a plurality of frames in a plurality of colors,such as, red, yellow, and green, for ease of recognition. As illustratedin FIG. 12D, mirror position adjustment guide pattern P3 may alsodisplay parts of respective four sides so as to render vertical andhorizontal positions without surrounding a whole periphery. Therefore, aposition of display mirror 3 can be adjusted without allowing a positionof reflection image P2 to incline with respect to image P1.

(4) Modifications

The first exemplary embodiment is merely one of various exemplaryembodiments of the present disclosure. The first exemplary embodimentcan be variously modified in accordance with a design, for example, aslong as the object of the present disclosure can be achieved.

For example, display unit 2 is not limited to a configuration includingliquid crystal panel 22 and light source device 23. Display unit 2 maybe configured, with respect to a diffuse transmission type screen, toallow laser light to perform scanning from behind the screen, and torender an image on the screen, for example. Display unit 2 may also beconfigured, with respect to a diffuse transmission type screen, to allowa projector to project an image from behind the screen, for example.Display unit 2 may also be a light emitting type display panel includingan Organic Light Emitting Diode (OLED), for example.

An image based on a captured image is not limited to the captured imageitself, but may be an image acquired by image processing the capturedimage and a Computer Graphics (CG) image created based on the capturedimage, for example. For example, since an image captured with camera 90at night becomes darker, an image based on a captured image may be animage acquired by performing a brightness correction on an imagecaptured with camera 90. An image based on a captured image may be animage in which an obstacle is extracted from the captured image withcamera 90, and then a Computer Graphics (CG) image illustrating theobstacle is superimposed on the captured image.

In display system 10, a number of pixels in the lengthwise of reflectionimage P2 is smaller than a number of pixels in the lengthwise of imageP1, and a number of pixels in the widthwise of reflection image P2 issmaller than a number of pixels in the widthwise of image P1. However,this is merely an example. For example, in display system 10, only anumber of pixels in one of the lengthwise and the widthwise ofreflection image P2 may be smaller than a number of pixels in thecorresponding direction (lengthwise or widthwise) of image P1.

In vehicle 100, cameras 90 may be disposed so as to capture rear viewimages of areas on both sides of vehicle 100, which have been viewablewith conventional door mirrors or fender mirrors. In this case,electronic mirror system 80 may be used as rear view mirrors forreplacements of conventional door mirrors or fender mirrors.

A moving body to which electronic mirror system 80 is applied is notlimited to vehicle 100. For example, electronic mirror system 80 isapplicable to moving bodies other than vehicle 100, such as motorcycles,trains, airplanes, construction machines, and ships. In other words, amoving body main body is not limited to a vehicle, but may be a mainbody of a moving body other than vehicle 100, such as a motorcycle, atrain, an airplane, a construction machine, or a ship. Further,electronic mirror system 80 may be used in an amusement facility or amedical facility, for example, instead of a moving body.

Second Exemplary Embodiment

Display system 10 g according to the present exemplary embodimentdiffers from display system 10 according to the first exemplaryembodiment in terms of mirror 7 disposed on optical path OP betweendisplay surface 21 and display mirror 3, as illustrated in FIG. 13.Hereinafter, elements similar to those in the first exemplary embodimentare given identical reference signs, and description of such elements isomitted as appropriate.

Mirror 7 is configured to reflect, toward display mirror 3, image P1from display surface 21. Mirror 7 and display mirror 3 are disposed onoptical path OP between display surface 21 and display mirror 3 (opticalpath of light output from display surface 21), in an order of mirror 7and display mirror 3.

In other words, mirror 7 is disposed on an opposite side to light sourcedevice 23, when viewed from liquid crystal panel 22, in other words, infront of liquid crystal panel 22, so that light output from displaysurface 21 is incident on mirror 7. Mirror 7 reflects, toward displaymirror 3, light output from display surface 21. Display mirror 3 isdisposed at a position so that light output from display surface 21 andreflected by mirror 7 is incident on display mirror 3. Display mirror 3reflects light output from display surface 21 and reflected by mirror 7toward eyes 201 of user 200.

Mirror 7 is a plane mirror. Mirror 7 includes, as an example, a glassbase material, and a reflection film made of a metal film formed on asurface of the base material. Therefore, on mirror 7, light output fromdisplay surface 21 is reflected on a surface of the reflection film.

In display system 10 g according to the present exemplary embodiment,display unit 2, mirror 7, and display mirror 3 are respectively disposedat apex positions of a triangle formed on a vertical surface. The term“vertical surface” used herein denotes a plane containing the lengthwise(vertical direction) of an image displayed on display unit 2 and anadvancing direction (optical axis) of output light. In display system 10g, light output from display surface 21 is first reflected by mirror 7,and then further reflected by display mirror 3.

Therefore, in display system 10 g according to the present exemplaryembodiment, light output from display surface 21 is reflected twice. Ina modification of display system 10 g, mirror 7 may be increased innumber so that light output from display surface 21 is reflected threetimes or more. In other words, display system 10 g may be configured toreflect light output from display surface 21 a plurality of times. Alength of an optical path between display surface 21 and eyes 201 ofuser 200 relates to a distance between a position at which virtual image300 being projected is viewable by eyes 201 of user 200 and eyes 201 ofuser 200. Therefore, in display system 10 g, by reflecting light outputfrom display surface 21 a plurality of times, a distance from eyes 201of user 200 to a position of virtual image 300 being projected can beextended. Display unit 2, the controller, display mirror 3, and mirror 7are accommodated in single housing 35 in display system 10 g. Withdisplay system 10 g, by making a distance from eyes 201 of user 200 tovirtual image 300 identical to the corresponding distance in displaysystem 10 according to the first exemplary embodiment, for example,display system 10 g can be reduced in size.

Display system 10 g may include an optical component (e.g., lens), otherthan mirror 7, on optical path OP between display surface 21 and displaymirror 3.

The configuration of display system 10 g according to the secondexemplary embodiment can be appropriately combined with any of theconfigurations of the modifications to the first exemplary embodiment.

Third Exemplary Embodiment

(1) Outline

Display system 10 according to the present exemplary embodiment is, asillustrated in FIG. 1, a system used in vehicle 100 representing amoving body, for example.

Display system 10 is mounted on main body (moving body main body) 110 ofvehicle 100. In display system 10, when image P1 based on a capturedimage is displayed on display surface 21, image (hereinafter alsoreferred to as reflection image) P2 (see FIGS. 3 and 14) reflected bydisplay mirror 3 is viewed by user 200 (driver of vehicle 100) who is asubject viewing display mirror 3. Display mirror 3 is disposed, proximalto windshield 102 , on a front side portion of ceiling portion 101 ofmain body 110, at a position in a viewing field of user 200, when user200 seated on front seat 103 faces forward (see FIG. 1). A capturedimage is output from camera (imaging device) 90 configured to capture arear view image of vehicle 100. Camera 90 is mounted on main body 110 ofvehicle 100. User 200 views reflection image P2 with display mirror 3.Therefore, user 200 views as if image P1 on display surface 21 isdisplayed in a space that is distal from display mirror 3, based ontheir eyes (eye balls) 201 (see FIGS. 5A and 5B). In other words, user200 views as if, in a direction in which user 200 can view displaymirror 3, virtual image 300 (see FIGS. 2 and 5A) of image P1 on displaysurface 21 is displayed at a position in front of vehicle 100.

With the electronic mirror system described in PTL 1, however, a driverof a vehicle views an actual image displayed on a display deviceincluding a liquid crystal display. Therefore, for the driver, forexample, a distance difference between a distance to a position at whicheyes focus on when viewing a road situation in front of the vehicle anda distance to a position at which the eyes focus on when viewing animage on the display device becomes greater, thus increasing an amountof focus adjustment and extending a time for focusing (focal pointadjustment).

On the other hand, with display system 10, as illustrated in FIG. 2, foruser 200, distance difference ΔL between distance L1 to a position atwhich eyes 201 focus on when viewing a road situation in front ofvehicle 100 and distance L2 to a position at which eyes 201 focus onwhen viewing virtual image 300 becomes smaller. Therefore, with displaysystem 10, user 200 can reduce an amount of focus adjustment, as well asuser 200 can shorten a time for focusing. With display system 10, evenwhen user 200 is aged or far sighted, for example, and accordingly facesdifficulty in focusing on a position at a relatively shorter distance,an easy focus adjustment can be achieved.

Display system 10 according to the present exemplary embodimentincludes, as illustrated in FIG. 14, display element 4 disposed onoptical path OP between display surface 21 and display mirror 3. Here,display element 4 displays, as pattern image PA1, a part of an objectpresent inside a visual field of display mirror 3 and outside visualfield FV9 of camera 90 (see FIG. 1). Here, as illustrated in FIG. 15B,display element 4 has first surface 41 and second surface 42, and isconfigured so that light that is incident on display element 4 via firstsurface 41 emits display element 4 via second surface 42. Therefore, indisplay system 10, user 200 viewing display mirror 3 views image P1displayed on display surface 21 and pattern image PA1 displayed ondisplay element 4 overlapping each other. Therefore, with display system10, user 200 can advantageously acquire a distance sense to anothervehicle, for example, behind vehicle 100, compared with a case when adriver directly views a display device displaying, as an image, an imagesignal output from an imaging device.

(2) Configuration

(2.1) Whole Configuration of Display System

Display system 10 according to the present exemplary embodimentincludes, as illustrated in FIGS. 1, 14, 2, 4, 5A, and 6A, display unit(image forming unit) 2, display mirror 3, and display element 4. Displayunit has display surface 21. In FIGS. 1, 2, 4, 5A, and 6A, illustrationof display element 4 is omitted. Display system 10 further includes acontroller (not illustrated) configured to control display unit 2.

Display surface 21 is configured to display image P1 based on a capturedimage output from camera 90. Camera 90 is not a component of displaysystem 10. An image element in camera 90 is a Complementary MOS (CMOS)image sensor. The image element is not limited to the CMOS image sensor,but may be a Charge Coupled Device (CCD) image sensor, for example.

Display unit 2 outputs light to form an image. Display unit 2 includes,as illustrated in FIG. 14, liquid crystal panel 22 (Liquid CrystalDisplay or LCD) and light source device 23. Liquid crystal panel 22 isdisposed in front of light source device 23. Light source device 23 isused as a backlight for liquid crystal panel 22. Light source device 23is a surface light source. Light source device 23 is a side light typelight source device using a solid light-emitting element, such as alight emitting diode or a laser diode. Light from light source device 23passes through liquid crystal panel 22, and is output from displaysurface 21 of display unit 2. Light output from display surface 21(output light) is light reflecting an image displayed on liquid crystalpanel 22. FIG. 14 schematically illustrates an advancing path (opticalpath OP) of light output from a point (pixel point) on image P1displayed on display surface 21 of display unit 2.

In display system 10, a lengthwise of liquid crystal panel 22 representsa lengthwise of reflection image P2, while a widthwise of liquid crystalpanel 22 represents a widthwise of reflection image P2. The lengthwiseof reflection image P2 represents a lengthwise of virtual image 300 (seeFIG. 4), in other words, a direction along a vertical direction in avisual field of user 200. The widthwise of reflection image P2represents a widthwise of virtual image 300, in other words, a directionalong a horizontal direction in the visual field of user 200.

The controller controls display unit 2 (liquid crystal panel 22 andlight source device 23). Here, the controller acquires a captured imageoutput from camera 90, and causes display unit 2 to display image P1based on the captured image. The captured image is a rear view image ofvehicle 100 captured and generated by camera 90 mounted on a rearportion of vehicle 100. As an example, the controller causes displayunit 2 to display, as image P1, an acquired captured image as is. Here,camera 90 is disposed on the rear portion of vehicle 100 at a center ina left-right direction. Therefore, camera 90 can capture an area behindcamera 90 (within visual field FV9 of camera 90). Display system 10 canbe applied to electronic mirror system 80. Electronic mirror system 80includes display system 10, and camera 90 configured to output acaptured image to display system 10. Electronic mirror system 80 can beused as an inside mirror of vehicle 100.

The controller includes, for example, a microcomputer mainly including aCentral Processing Unit (CPU) and a memory. In other words, thecontroller is achieved by using a computer including a CPU and a memory.The CPU executes a program stored in the memory, allowing the computerto function as the controller. Herein, the program is recorded inadvance in the memory of the controller. However, the program may beprovided via a telecommunication line such as the Internet or by beingrecorded in a recording medium such as a memory card.

Display mirror 3 is a concave mirror. Display mirror 3 includes, as anexample, a glass base material, and a reflection film formed on aconcave surface of the base material. The reflection film is a metalfilm, for example.

Display mirror 3 is configured to reflect image P1 displayed on displaysurface 21. Display mirror 3 in display system 10 reflects, asreflection image P2, only a partial area in image P1 displayed ondisplay surface 21.

In display system 10, as illustrated in FIG. 4, a size of display mirror3 is determined so that a size of virtual image 300, with respect towhole image P1, on a virtual plane in a space away from user 200 isgreater than a size of visual field VF2 of eyes 201 of user 200, whichis determined by display mirror 3. Here, in display system 10, the sizeof display mirror 3 is determined so that an outer peripheral line ofvisual field VF2 on the above described virtual plane lies inside anouter peripheral line of virtual image 300. Therefore, display system 10is configured so that a position of reflection image P2 displayed asvirtual image 301 at a distal position changes as eyes 201 of user 200(subject) viewing display mirror 3 move (see FIGS. 5A, 5B, 6A, and 6B).Here, reflection image P2 has a less number of pixels than a number ofpixels in image P1 in both the lengthwise and the widthwise of image P1.

For description purposes, two eyes 201 of user 200 hereinafter may bereferred to as right eye 201R and left eye 201L to distinguish from eachother. In below descriptions with reference to FIGS. 5A and 6A, the term“right side” refers to a right side when viewed by user 200, while theterm “left side” refers to a left side when viewed by user 200. Indisplay system 10, when a size of display surface 21 is determined inadvance, a radius of curvature of display mirror 3 may be determined sothat a size of virtual image 301 is greater than a size of visual fieldVF2.

FIG. 5A is a conceptual diagram when a center point of a straight lineconnecting right eye 201R and left eye 201L of user 200 and a center ofdisplay surface 21 both lie within vertical surface VP. FIG. 6A is aconceptual diagram when the center point of the straight line connectingright eye 201R and left eye 201L of user 200 moves rightward from theposition in FIG. 5A, and right eye 201R moves to a right end of eye-box203. The term “eye-box 203” used herein denotes an area within whichuser 200 can view an image without any omissions. More specifically, theterm “eye-box 203” used herein denotes an area of view in a whole visualfield of eyes 201, in which a part of virtual image 300 is displayed. Indisplay system 10, when eyes 201 of user 200 are within an area ofeye-box 203, reflection image P2 is within image P1, as illustrated inFIGS. 5B and 6B.

As illustrated in FIGS. 5A and 6A, virtual image 301 formed when displaymirror 3 reflects a part of image P1 represents a part of virtual image300 formed when image P1 displayed on display surface 21 is fullyreflected by a concave mirror 30 according to the comparative example(see FIGS. 7 and 8). In FIG. 5A, a central portion of whole virtualimage 300 in both an up-down direction and a left-right directionrepresents virtual image 301 that is viewable by user 200.

FIG. 5A illustrates an area of virtual image 301 in virtual image 300,which is viewable by right eye 201R of user 200. An area of virtualimage 301, which is viewable by left eye 201L of user 200, is planesymmetry to the area of virtual image 301, which is viewable by righteye 201R, with respect to vertical surface VP.

As illustrated in FIG. 6A, as the center point on the straight lineconnecting right eye 201R and left eye 201L of user 200 moves rightwardrelative to the position illustrated in FIG. 5A, the area of virtualimage 301, which is viewable by right eye 201R of user 200 movesleftward. In FIG. 6A, right eye 201R of user 200 lies at right end 203Rof eye-box 203, and left end 301L of virtual image 301, which isviewable by right eye 201R of user 200, is in alignment with left end300L of virtual image 300.

In contrast to FIG. 6A, as the center point on the straight lineconnecting right eye 201R and left eye 201L of user 200 moves leftwardrelative to the position illustrated in FIG. 5A, the area of virtualimage 301, which is viewable by left eye 201L of user 200, movesrightward. When left eye 201L of user 200 moves to left end 203L ofeye-box 203, right end 301R of virtual image 301, which is viewable byleft eye 201L of user 200, is in alignment with right end 300R ofvirtual image 300.

Therefore, in display system 10, when user 200 moves their face in theleft-right direction, similar to a case when user 200 views aconventional inside mirror in a vehicle, the areas of virtual image 301,which are respectively viewable by right eye 201R and left eye 201L,change as user 200 moves their face. Here, as long as right eye 201R andleft eye 201L of user 200 are within eye-box 203, an image can be viewedwithout any omissions.

In display system 10, even when user 200 moves their face in the up-downdirection, similar to a case when user 200 views the inside mirror, theareas of virtual image 301, which are respectively viewable by right eye201R and left eye 201L, change as user 200 moves their face. In otherwords, when user 200 moves their face upward, the areas of virtual image301, which are respectively viewable by right eye 201R and left eye201L, move downward, while, when user 200 moves their face downward, theareas of virtual image 301, which are respectively viewable by right eye201R and left eye 201L, move upward. Here, as long as right eye 201R andleft eye 201L of user 200 are within eye-box 203, an image can be viewedwithout any omissions.

Display element 4 is disposed on optical path OP between display surface21 and display mirror 3. Display element 4 is an element configured todisplay, as pattern image PA1 (see FIGS. 14 and 15A), at least a part ofan object present inside a visual field of display mirror 3 and outsidevisual field FV9 of camera 90. Here, at least parts of objects arepillars 105 of vehicle 100 (see FIG. 1). Pillars 105 used herein denotewindow pillars diagonally behind a rear seat in vehicle 100. Patternimage PA1 includes, as an example, two image portions PA1l, imageportion PA12, and image portion PA13. Two image portions PAHrespectively correspond, one by one, to two pillars 105 that areseparate from each other on left and right of vehicle 100. Image portionPA12 corresponds to a rear portion of ceiling portion 101 coupled toupper ends of two pillars 105 of vehicle 100 (see FIG. 1). Image portionPA13 corresponds to a portion coupled to lower ends of two pillars 105of vehicle 100. Pattern image PA1 is not limited to the exampleillustrated in FIG. 14, as long as pattern image PA1 includes at leasttwo image portions PAH which respectively correspond, one by one, to twopillars 105, for example. A thickness of each of image portions PA1lcorresponding to pillars 105 may be changed in accordance with a vehicletype of vehicle 100, for example, or may be thinner than a thickness ofeach of pillars 105 of vehicle 100.

Display element 4 includes, as illustrated in FIGS. 15A and 15B,transparent plate 40 and pattern image PA1. Transparent plate 40 isformed into a rectangular plate shape, and has first surface 41 andsecond surface 42 facing each other in a thickness direction. Firstsurface 41 and second surface 42 are each formed into a plane shape.First surface 41 and second surface 42 are parallel to each other. Inother words, transparent plate 40 has a constant thickness. Patternimage PA1 is formed on first surface 41 of transparent plate 40.However, this is merely an example. Pattern image PA1 may be formed onsecond surface 42 of transparent plate 40. Pattern image PA1 is formedthrough a printing technique. In other words, pattern image PA1 is aprinted film having a predetermined pattern.

Display element 4 is disposed, on optical path OP, proximal to displaysurface 21. Display element 4 is disposed so that, among first surface41 and second surface 42, second surface 42 serves as display surface21. On optical path OP, a distance between display element 4 and displaysurface 21 is shorter than a distance between display element 4 anddisplay mirror 3.

Transparent plate 40 is made of glass, and has transparency, forexample. As for the term “having transparency” used herein, apenetration rate with respect to visible light may be 50% or higher, maybe preferably 70% or higher, or may be further preferably 90% or higher.The transparent plate is not limited to glass, and may be made of resin,such as acrylic resin.

Display system 10 according to the present exemplary embodiment includesdisplay element 4 between display surface 21 and display mirror 3,allowing user 200 viewing display mirror 3 to view image P1 and patternimage PA1 overlapping each other (see reflection image P2 illustrated inFIG. 14). Therefore, with display system 10, user 200 viewing an image(reflection image P2) displayed by display system 10 can advantageouslyacquire a distance sense to another following vehicle, for example, byusing pattern image PA1 as a reference (mark), compared with a case whena driver directly views a display device displaying, as an image, animage signal output from an imaging device, similar to a conventionalelectronic mirror system.

In display system 10 including display surface 21 configured to displayimage P1 based on a captured image, and display mirror 3 configured toreflect image P1 displayed on display surface 21, it is advantageousthat a resolution of image P1 displayed on display surface 21 be higherthan a limit resolution of virtual image 300 at a position of virtualimage 300 being displayed. The term “limit resolution of virtual image300 at a position of virtual image 300 being displayed” (hereinaftersimply referred to as limit resolution) used herein denotes a valuedetermined by a visual distance from eyes 201 of user 200 to virtualimage 300 and visual acuity of user 200. A limit resolution refers to alimit value of a resolution identifiable by human's eyes, and can beacquired based on a gap of a Landolt ring used in a visual acuity test,for example. When a visual distance extends longer, a value of a limitresolution becomes smaller. When user 200 has higher visual acuity, avalue of a limit resolution becomes greater. A limit resolution can beacquired from a predetermined calculating formula with a value of avisual distance from eyes 201 of user 200 to virtual image 300 and avalue of visual acuity of user 200. In display system 10 according tothe present exemplary embodiment, display mirror 3 expands and displaysa part of an image on display surface 21, thus determining, when a limitresolution is determined, a resolution of image P1 on display surface 21in accordance with the limit resolution, and setting a resolution ofimage P1 to a value that is higher than a value of the limit resolution.As described above, once a resolution of image P1 on display surface 21is determined, virtual image 300 is displayed at a resolution that ishigher than a limit resolution at a position of virtual image 300 beingdisplayed, thus providing, to user 200 viewing virtual image 300, asense of depth and a sense of solidity in virtual image 300, as if user200 is viewing a mirror. In particular, while vehicle 100 is traveling,a high-definition image moves as vehicle 100 moves, and user 200 canfurther acquire a sense of solidity.

In display system 10, housing 28 accommodating display unit 2, displayelement 4, and the controller, and housing 38 accommodating displaymirror 3 are separate from each other. However, this is merely anexample, and display unit 2, display element 4, the controller, anddisplay mirror 3 may be accommodated in a single housing, for example.

(2.2) Operation of Electronic Mirror System

Operation of electronic mirror system 80 will now be described.

For example, when a battery of vehicle 100 supplies power to electronicmirror system 80, and an Electronic Control Unit (ECU) enters a controlsignal causing electronic mirror system 80 to start operating,electronic mirror system 80 starts operating.

For example, when the ECU of vehicle 100 enters a control signal to thecontroller, the controller causes camera 90 to capture a rear view imageof vehicle 100 at a predetermined frame rate, and acquires image data onthe captured image from camera 90.

When the image data on the captured image is entered from camera 90, thecontroller causes display unit 2 to display, on display surface 21,image P1 based on the captured image.

A part of image P1 displayed on display surface 21 of display unit 2 isreflected by display mirror 3. Therefore, user 200 can view reflectionimage P2 on which image P1 and pattern image PA1 overlap each other.

(3) Modifications

Third exemplary embodiment is merely one of various exemplaryembodiments of the present disclosure. The third exemplary embodimentcan be variously modified in accordance with a design, for example, aslong as the object of the present disclosure can be achieved.

(3.1) First Modification

Display system 10 according to the first modification differs fromdisplay system 10 according to the third exemplary embodiment in termsof display element 4 a (see FIGS. 16A, 16B, and 16C) having aconfiguration that differs from the configuration of display element 4of display system 10 according to the third exemplary embodiment.Elements similar to those in the third exemplary embodiment are givenidentical reference signs, and description of such elements is omittedas appropriate.

Display element 4 a includes transparent plate 40, first pattern imageelement 43, and second pattern image element 44. Transparent plate 40has first surface 41 and second surface 42 facing each other in athickness direction. In display element 4a, on optical path OP, firstsurface 41 is proximal to display mirror 3, while second surface 42 isproximal to display surface 21.

First pattern image element 43 is formed on first surface 41 oftransparent plate 40. First pattern image element 43 has a shapeidentical to a shape of pattern image PA1, and originates pattern imagePA1. Second pattern image element 44 is formed on second surface 42 oftransparent plate 40. Second pattern image element 44 has a shapeidentical to a shape of pattern image PA1, and originates pattern imagePA1. First pattern image element 43 and second pattern image element 44are disposed so as to overlap each other in the thickness direction oftransparent plate 40.

In display element 4a, brightness distribution in first pattern imageelement 43 and brightness distribution in second pattern image element44 differ from each other.

Among first pattern image element 43 and second pattern image element44, on first pattern image element 43 that is proximal to display mirror3 on optical path OP, a portion of an actual object corresponding topattern image PA1, which is relatively proximal to display mirror 3,becomes brighter. On the other hand, among first pattern image element43 and second pattern image element 44, on second pattern image element44 that is distal from display mirror 3 on optical path OP, a portion ofthe actual object corresponding to pattern image PA1, which isrelatively distal from display mirror 3, becomes brighter. In displaysystem 10, light from display unit 2 enters into display element 4a, andexits from display element 4a. Therefore, brightness distribution infirst pattern image element 43 and brightness distribution in secondpattern image element 44 differ from each other. In other words, displayelement 4 a is a Depth-Fused 3-D (DFD) display element. Therefore, user200 viewing display mirror 3 of display system 10 can view an imagefurther three-dimensionally due to illusion, and thus can easily acquirea distance sense to another following vehicle, for example.

(3.2) Second Modification

Display system 10 according to the second modification differs fromdisplay system 10 according to the third exemplary embodiment in termsof display element 4 b (see FIG. 17) having a configuration that differsfrom the configuration of display element 4 of display system 10according to the third exemplary embodiment.

Display element 4 b includes transparent block 45, and pattern image PA1formed inside transparent block 45. Display element 4 b isthree-dimensional (3D) crystal glass, in which transparent block 45 madeof crystal glass is provided, and pattern image PA1 based on a modifiedportion of crystal glass is provided. The modified portion is formed bylaser machining crystal glass.

(3.3) Third Modification

Display system 10 according to the third modification differs fromdisplay system 10 according to the third exemplary embodiment in termsof display element 4 c (see FIGS. 18A and 18B) having a configurationthat differs from the configuration of display element 4 of displaysystem 10 according to the third exemplary embodiment.

Display element 4 c is a transparent display. The transparent display isa display capable of displaying pattern image PA1 on a transparentscreen.

The transparent display is a transparent liquid crystal display.However, this is merely an example. The transparent display may be anOLED display, for example. Display element 4 c is controlled by thecontroller to switch between a state in which pattern image PA1 isdisplayed, as illustrated in FIG. 18A, and a state in which patternimage PA1 is not displayed, as illustrated in FIG. 18B, for example.

(3.4) Fourth Modification

Display system 10 according to the fourth modification differs fromdisplay system 10 according to the third exemplary embodiment in termsof Depth-Fused 3-D (DFD) display 6, different from display system 10according to the third exemplary embodiment (see FIG. 19).

DFD display 6 is a display utilizing a three dimensional illusionphenomenon. DFD display 6 includes two image display panels 61, 62. DFDdisplay 6 further includes light source device 63. In DFD display 6,among two image display panels 61, 62, a screen of image display panel61 (hereinafter also referred to as first image display panel 61) thatis distal from display mirror 3 serves as display surface 21. In DFDdisplay 6, image display panel 62 (hereinafter also referred to assecond image display panel 62) that is proximal to display mirror 3serves as display element 4d configured to display pattern image PA1. Inother words, first image display panel 61 is configured to display imageP1 based on a captured image. Second image display panel 62 isconfigured to display pattern image PA1.

Two image display panels 61, 62 are liquid crystal panels. Light sourcedevice 63 is used as a backlight for two image display panels 61, 62.Light source device 63 is a surface light source. Two image displaypanels 61, 62 and light source device 63 of DFD display 6 are controlledby the controller.

(3.5) Fifth Modification

Display system 10 according to the fifth modification is substantiallyidentical to display system 10 according to the third exemplaryembodiment, but differs from display system 10 according to the thirdexemplary embodiment in that display element 4 is rotatable between afirst position on optical path OP between display surface 21 and displaymirror 3 and a second position outside optical path OP, as illustratedin FIG. 20.

(3.6) Sixth Modification

Display system 10 according to the sixth modification is configured todisplay an image acquired by combining and overlapping captured imagesrespectively output from camera 90 (first camera 90) configured tocapture a rear view image of vehicle 100, a second camera configured tocapture a right rear view image of vehicle 100, and a third cameraconfigured to capture a left rear view image of vehicle 100, with anobject, such as a pillar of vehicle 100. FIG. 21 is an example of aconceptual diagram illustrating an image reflected by a display mirrorin display system 10 according to the sixth modification.

(3.7) Other Modifications

The following includes modifications to the third exemplary embodiment,other than the first to sixth modifications.

Display unit 2 is not limited to a configuration including liquidcrystal panel 22 and light source device 23. Display unit 2 may beconfigured, with respect to a diffuse transmission type screen, to allowlaser light to perform scanning from behind the screen, and to render animage on the screen, for example. Display unit 2 may also be configured,with respect to a diffuse transmission type screen, to allow a projectorto project an image from behind the screen, for example. Display unit 2may also be a light emitting type display panel including an OrganicLight Emitting Diode (OLED), for example.

An image based on a captured image is not limited to the captured imageitself, but may be an image acquired by image processing the capturedimage and a Computer Graphics (CG) image created based on the capturedimage, for example. For example, since an image captured with camera 90at night becomes darker, an image based on a captured image may be animage acquired by performing a brightness correction on an imagecaptured with camera 90. An image based on a captured image may be animage in which an obstacle is extracted from the captured image ofcamera 90, and then a Computer Graphics (CG) image illustrating theobstacle is superimposed on the captured image.

In display system 10, a number of pixels in the lengthwise of reflectionimage P2 is smaller than a number of pixels in the lengthwise of imageP1, and a number of pixels in the widthwise of reflection image P2 issmaller than a number of pixels in the widthwise of image P1. However,this is merely an example. For example, in display system 10, only anumber of pixels in one of the lengthwise and the widthwise ofreflection image P2 may be smaller than a number of pixels in thecorresponding direction (lengthwise or widthwise) of image P1.

In display system 10, pattern image PA1 of display element 4 may be atranslucent printed film. Therefore, blind spots are reduced for user200 viewing display mirror 3.

Display system 10 may include a DFD display instead of display element4. A DFD display is a display utilizing a three dimensional illusionphenomenon. In this case, the DFD display includes, on optical path OP,a first liquid crystal panel disposed to face display mirror 3, and asecond liquid crystal panel disposed to face display surface 21. Here,the first liquid crystal panel displays an image containing a firstpattern image element having brightness distribution similar to thebrightness distribution in the first pattern image element described inthe first modification. The second liquid crystal panel displays animage containing a second pattern image element having brightnessdistribution similar to the brightness distribution in the secondpattern image element described in the first modification.

In display system 10, display element 4 is disposed parallel to displaysurface 21. However, display element 4 may be disposed so as to be awayfrom display surface 21 with respect to its upper and lower sides.Therefore, user 200 viewing display system 10 can view an imagethree-dimensionally, compared with a case in which display element 4 isdisposed parallel to display surface 21.

Display element 4 is configured such that a pattern image is formed onthe flat plate. However, a three-dimensional structure may be applied.Therefore, user 200 viewing display system 10 can view an imagethree-dimensionally, compared with a case in which display element 4 isa pattern image on a flat plate.

In vehicle 100, cameras 90 may be disposed so as to capture rear viewimages of areas on both sides of vehicle 100, which have been viewablewith conventional door mirrors or fender mirrors. In this case,electronic mirror system 80 may be used as rear view mirrors forreplacements of conventional door mirrors or fender mirrors.

A moving body to which electronic mirror system 80 is applied is notlimited to vehicle 100. For example, electronic mirror system 80 isapplicable to moving bodies other than vehicle 100, such as motorcycles,trains, airplanes, construction machines, and ships. In other words, amoving body main body is not limited to a vehicle, but may be a mainbody of a moving body other than vehicle 100, such as a motorcycle, atrain, an airplane, a construction machine, or a ship. Further,electronic mirror system 80 may be used in an amusement facility or amedical facility, for example, instead of a moving body.

Fourth Exemplary Embodiment

Display system 10 h according to the present exemplary embodimentdiffers from, as illustrated in FIG. 22, display system 10 according tothe third exemplary embodiment in terms of mirror 7 disposed on opticalpath OP between display surface 21 and display mirror 3. Hereinafter,elements similar to those in the third exemplary embodiment are givenidentical reference signs, and description of such elements is omittedas appropriate.

Mirror 7 is configured to reflect, toward display mirror 3, image P1from display surface 21. Display element 4, mirror 7, and display mirror3 are disposed on optical path OP between display surface 21 and displaymirror 3 (optical path of light output from display surface 21) in anorder of display element 4, mirror 7, and display mirror 3.

In other words, mirror 7 is disposed on an opposite side to light sourcedevice 23, when viewed from liquid crystal panel 22, in other words, infront of liquid crystal panel 22, so that light from display surface 21(hereinafter also referred to as output light) is incident on mirror 7via display element 4. Mirror 7 reflects, toward display mirror 3, lightoutput from display surface 21. Display mirror 3 is disposed at aposition so that light output from display surface 21 and reflected bymirror 7 is incident on display mirror 3. Display mirror 3 reflectslight output from display surface 21 and reflected by mirror 7 towardeyes 201 of user 200.

Mirror 7 is a plane mirror. Mirror 7 includes, as an example, a glassbase material, and a reflection film made of a metal film formed on asurface of the base material. Therefore, on mirror 7, light output fromdisplay surface 21 is reflected on a surface of the reflection film.

In display system 10 h according to the present exemplary embodiment,display unit 2, mirror 7, and display mirror 3 are respectively disposedat apex positions of a triangle formed on a vertical surface. The term“vertical surface” used herein denotes a plane containing the lengthwise(vertical direction) of an image displayed on display unit 2 and anadvancing direction (optical axis) of output light. In display system 10h, light output from display surface 21 is first reflected by mirror 7,and then further reflected by display mirror 3.

Therefore, in display system 10 h according to the present exemplaryembodiment, light output from display surface 21 is reflected twice. Ina modification of display system 10 h, mirror 7 may be increased innumber so that light output from display surface 21 is reflected threetimes or more. In other words, display system 10 h may be configured toreflect light output from display surface 21 a plurality of times. Alength of an optical path between display surface 21 and eyes 201 ofuser 200 relates to a distance between a position at which virtual image300 being projected is viewable by eyes 201 of user 200 and eyes 201 ofuser 200. Therefore, in display system 10 h, by reflecting light outputfrom display surface 21 a plurality of times, a distance from eyes 201of user 200 to a position of virtual image 300 being projected can beextended.

Display unit 2, the controller, display element 4, display mirror 3, andmirror 7 are accommodated in single housing 35 in display system 10 h.With display system 10 h, by making a distance from eyes 201 of user 200to virtual image 300 identical to the corresponding distance in displaysystem 10 according to the third exemplary embodiment, for example,display system 10 h can be reduced in size.

Display system 10 h may include an optical component (e.g., lens), otherthan mirror 7, on optical path OP between display surface 21 and displaymirror 3.

The configuration of display system 10 h according to the fourthexemplary embodiment (including the modifications) can be appropriatelycombined with the configurations of the first to sixth modifications ofthe third exemplary embodiment.

(Summary)

As described above, display system (10; 10 g) according to a firstaspect includes display surface (21) and display mirror (3). Displaysurface (21) is configured to display image (P1) based on a capturedimage. Display mirror (3) is configured to reflect, as reflection image(P2), only a partial area in image (P1) displayed on display surface(21). Display system (10; 10 g) is configured so that a position ofreflection image (P2) changes as a point of view of a subject (e.g.,user 200) viewing display mirror (3) moves.

With this configuration, display mirror (3) reflects, as reflectionimage (P2), only a partial area in image (P1) displayed on displaysurface (21), different from a mirror reflecting a whole area in animage displayed on a liquid crystal display. Here, display system (10;10 g) is configured so that a position of reflection image (P2) of image(P1) changes as a point of view (eyes 201 of user 200) of a subject(e.g., user 200) viewing display mirror (3) moves. Therefore, displaysystem (10; 10 g) is capable of advantageously providing a sense ofsolidity to a person (subject) viewing a displayed image.

In display system (10; 10 g) according to a second aspect, in the firstaspect, when a point of view of a subject (e.g., user 200) is within anarea of eye-box (203), reflection image (P2) is within image (P1).

With this configuration, an image can be viewed without any omissions.

In display system (10; 10 g) according to a third aspect, in the firstor second aspect, display mirror (3) is a concave mirror.

With this configuration, a person viewing display mirror (3) of displaysystem (10; 10 g) can easily view reflection image (P2) furtherthree-dimensionally, compared with a case in which display mirror (3) isa plane mirror.

Display system (10; 10 g) according to a fourth aspect further includes,in any one of the first to third aspects, mirror (7) disposed on opticalpath (OP) between display surface (21) and display mirror (3), andconfigured to reflect image (P1) from display surface (21) to displaymirror (3).

With this configuration, a length of the optical path between displaysurface (21) and a point of view of a subject (e.g., user 200) can beextended.

In display system (10; 10 g) according to a fifth aspect, in any one ofthe first to fourth aspects, reflection image (P2) has a less number ofpixels than a number of pixels in image (P1) in both the lengthwise andthe widthwise of image (P1).

With this configuration, even when a position of reflection image (P2)changes in either or both of the lengthwise and the widthwise of image(P1), the image can be viewed without any omissions.

Electronic mirror system (80) according to a sixth aspect includesdisplay system (10; 10 g) according to any one of the first to fifthaspects, and camera (90) configured to output a captured image todisplay system (10; 10 g).

This configuration is capable of advantageously providing a sense ofsolidity to a person (subject) viewing a displayed image.

A moving body (e.g., vehicle 100) according to a seventh aspect includeselectronic mirror system (80) according to the sixth aspect, and amoving body main body (e.g., main body 110 of vehicle 100) mounted withelectronic mirror system (80).

This configuration is capable of advantageously providing a sense ofsolidity to a person (subject) viewing a displayed image.

Display system (10; 10 g) according to an eighth aspect includes displaysurface (21) configured to display image (P1) based on a captured image,and display mirror (3) configured to reflect image (P1) displayed ondisplay surface (21). A resolution of display surface (21) is higherthan a limit resolution of an image displayed at a predeterminedposition by display mirror (3). The eighth aspect is an aspect that canbe solely implemented, in which any one of the first to fifth aspects isnot essential as a prerequisite.

Display system (10; 10 h) according to a ninth aspect includes displaysurface (21), display mirror (3), and display element (4; 4 a; 4 b; 4 c;4 d). Display surface (21) is configured to display image (P1) based ona captured image output from camera (90). Display mirror (3) isconfigured to reflect image (P1) displayed on display surface (21).Display element (4; 4 a; 4 b; 4 c; 4 d) is disposed on optical path (P1)between display surface (21) and display mirror (3). Display element (4)displays, as pattern image (PA1), at least a part of an object presentinside a visual field of display mirror (3) and outside visual field(FV9) of camera (90).

With this configuration, a subject viewing display mirror (3) viewsthree-dimensionally image (P1) and pattern image (PA1) overlapping eachother. Therefore, with display system (10; 10 h), a person viewing animage displayed by display system (10; 10 h) can advantageously acquirea distance sense, by using pattern image (PA1) as a reference (mark),compared with a case when a person directly views a display devicedisplaying, as an image, an image signal output from an imaging device,similar to a conventional electronic mirror system.

In display system (10; 10 h) according to a tenth aspect, in the ninthaspect, display element (4) includes transparent plate (40) and patternimage (PA1). Transparent plate (40) has first surface (41) and secondsurface (42) facing each other in the thickness direction. Pattern image(PA1) is formed on one of first surface (41) and second surface (42).

With this configuration, display element (4) can be achieved in arelatively simple configuration.

In display system (10; 10 h) according to an eleventh aspect, in theninth aspect, display element (4a) includes transparent plate (40),first pattern image element (43), and second pattern image element (44).Transparent plate (40) has first surface (41) and second surface (42)facing each other in the thickness direction. First pattern imageelement (43) is formed on first surface (41) of transparent plate (40).First pattern image element (43) has a shape identical to a shape ofpattern image (PA1), and originates pattern image (PA1). Second patternimage element (44) is formed on second surface (42) of transparent plate(40). Second pattern image element (44) has a shape identical to a shapeof pattern image (PA1), and originates pattern image (PA1). Brightnessdistribution in first pattern image element (43) and brightnessdistribution in second pattern image element (44) differ from eachother.

With this configuration, a person viewing display mirror (3) of displaysystem (10; 10 h) can view an image further three-dimensionally due toillusion, and thus can easily acquire a distance sense. In displaysystem (10; 10 h) according to a twelfth aspect, in the ninth aspect,display element (4b) includes transparent block (45), and pattern image(PA1) formed inside transparent block (45).

This configuration advantageously prevents, as much as possible, qualityof an image from lowering due to dirt and scratch, for example, onpattern image (PA1).

In display system (10; 10 h) according to a thirteenth aspect, in theninth aspect, display element (4 c) is a transparent display.

This configuration advantageously prevents, as much as possible, qualityof an image from lowering due to dirt and scratch, for example, onpattern image (PA1), advantageously disallows pattern image (PA1) frombeing displayed as required, and advantageously easily allows a changein pattern image (PA1).

Display system (10; 10 h) according to a fourteenth aspect includes, inthe ninth aspect, DFD display (6) including two image display panels(61, 62). Among two image display panels (61, 62), a screen of imagedisplay panel (61) that is distal from display mirror (3) serves asdisplay surface (21), while image display panel (62) that is proximal todisplay mirror (3) serves as display element (4d).

This configuration advantageously disallows pattern image (PA1) frombeing displayed as required, and advantageously allows a change inpattern image (PA1).

In display system (10; 10 h) according to a fifteenth aspect, in any oneof the first to sixth aspect, display mirror (3) is a concave mirror.

With this configuration, a person viewing display mirror (3) of displaysystem (10; 10 h) can view an image further three-dimensionally, andthus can easily acquire a distance sense, compared with a case in whichdisplay mirror (3) is a plane mirror.

Electronic mirror system (80) according to a sixteenth aspect includesdisplay system (10; 10 h) according to any one of the first to seventhaspects, and camera (90) configured to output a captured image todisplay system (10; 10 h).

With this configuration, a person viewing an image displayed by displaysystem (10; 10 h) can advantageously acquire a distance sense, comparedwith a case when a person directly views a display device displaying, asan image, an image signal output from an imaging device, similar to aconventional electronic mirror system.

A moving body (e.g., vehicle 100) according to a seventeenth aspectincludes electronic mirror system (80) according to the sixteenthaspect, and a moving body main body (e.g., main body 110 of vehicle 100)mounted with electronic mirror system (80).

With this configuration, a person viewing an image displayed by displaysystem (10; 10 h) of electronic mirror system (80) can advantageouslyacquire a distance sense.

Display system (10; 10 h) according to an eighteenth aspect includesdisplay surface (21) configured to display image (P1) based on acaptured image, and display mirror (3) configured to reflect image (P1)displayed on display surface (21). A resolution of display surface (21)is higher than a limit resolution of an image displayed at apredetermined position by display mirror (3). The eighteenth aspect isan aspect that can be solely implemented, in which any one of the firstto seventh aspects is not essential as a prerequisite.

1. A display system comprising: a display surface configured to displayan image based on a captured image output from a camera; a displaymirror configured to reflect, as a reflection image, only a partial areain the image displayed on the display surface, wherein the displaysystem is configured so that a position of the reflection image changesas a point of view of a subject viewing the display mirror moves.
 2. Thedisplay system according to claim 1 further comprising a mirror disposedon an optical path between the display surface and the display mirror,the mirror being configured to reflect the image from the displaysurface to the display mirror.
 3. The display system according to claim1, wherein the reflection image has a less number of pixels than anumber of pixels in the image displayed on the display surface in both alengthwise and a widthwise of the image.
 4. The display system accordingto claim 1, wherein the only a number of pixels in one of the lengthwiseand the widthwise of reflection image is smaller than a number of pixelsin the corresponding direction of image displayed on the displaysurface.
 5. The display system according to claim 1, wherein the displaysurface is configured to switch whether to display a guide pattern imageto be used to adjust a position at which the reflection image islocated.
 6. An electronic mirror system comprising: the display systemaccording to claim 1; and a camera configured to output the capturedimage to the display system.
 7. A moving body comprising: the electronicmirror system according to claim 6; and a main body mounted with theelectronic mirror system.
 8. A display system comprising: a displaysurface configured to display an image based on a captured image outputfrom a camera; a display mirror configured to reflect, as a reflectionimage, only a partial area in the image displayed on the displaysurface, wherein the display system is configured so that a position ofthe reflection image changes as a point of view of a subject viewing thedisplay mirror moves, wherein, when the point of view of the subject iswithin an area of an eye-box, the reflection image area is within theimage displayed on the display surface.
 9. The display system accordingto claim 8 wherein the reflection image has a less number of pixels thana number of pixels in the image displayed on the display surface in botha lengthwise and a widthwise of the image.
 10. The display systemaccording to claim 8, wherein the only a number of pixels in one of thelengthwise and the widthwise of reflection image is smaller than anumber of pixels in the corresponding direction of image displayed onthe display surface.
 11. An electronic mirror system comprising: thedisplay system according to claim 9; and a camera configured to outputthe captured image to the display system.
 12. A moving body comprising:the electronic mirror system according to claim 11; and a main bodymounted with the electronic mirror system.
 13. A display systemcomprising: a display surface configured to display an image based on acaptured image output from a camera; a display mirror configured toreflect, as a reflection image, only a partial area in the imagedisplayed on the display surface, display element disposed on an opticalpath between the display surface and the display mirror, a the displayelement being configured to display, as a pattern image, at least a partof an object present inside a visual field of the display mirror andoutside a visual field of the camera, wherein the display system isconfigured so that a position of the reflection image changes as a pointof view of a subject viewing the display mirror moves,
 14. The displaysystem according to claim 13, wherein the display element includes: atransparent plate having a first surface and a second surface facingeach other in a thickness direction; and the pattern image formed on oneof the first surface and the second surface.
 15. The display systemaccording to claim 13, wherein the display element includes: atransparent plate having a first surface and a second surface facingeach other in a thickness direction; a first pattern image elementformed on the first surface of the transparent plate, the first patternimage element having a shape identical to a shape of the pattern image,the first pattern image based on which the pattern image is generated;and a second pattern image element formed on the second surface of thetransparent plate, the second pattern image having a shape identical toa shape of the pattern image, the second pattern image based on whichthe pattern image is generated, wherein brightness distribution in thefirst pattern image element and brightness distribution in the secondpattern image element differ from each other.
 16. The display systemaccording to claim 13, wherein the display element includes: atransparent block; and the pattern image formed inside the transparentblock.
 17. The display system according to claim 13, wherein the displayelement is a transparent display.
 18. The display system according toclaim 13, further comprising a Depth-Fused 3-D (DFD) display includingtwo image display panels, among the two image display panels, a screenof one of the image display panels serves as the display surface, andanother one of the image display panels serves as the display element,the one of the image display panels being distal from the displaymirror, and the other one of the image display panels being proximal tothe display mirror,.
 19. An electronic mirror system comprising: thedisplay system according to claim 13; and a camera configured to outputthe captured image to the display system.
 20. A moving body comprising:the electronic mirror system according to claim 19; and a main bodymounted with the electronic mirror system.